The present invention relates to a mechanical-hydrostatic transmission, particularly for tools and vehicles suitable for gardening, such as lawn-mowers or the like.
It is known that tools are currently used in the field of gardening or similar fields and are usually fitted on self-propelled vehicles, allowing the operator to perform various kinds of operation and work with limited effort and very rapidly.
The operating capabilities of these vehicles and of the tools installed thereon depend to a good extent on their mechanical structure, which as a whole must be compact, sturdy and adapted to ensure considerable flexibility in application, since the operating conditions can be the most disparate and demanding.
Such vehicles are usually provided with an engine which requires a mechanical transmission for moving the driving wheels.
Currently, notwithstanding the variety of commercially available types, mechanical transmissions for such vehicles comprise a reduction unit, a clutch unit arranged within a casing and, associated with said casing, auxiliary casings which accommodate an oil pump and a hydraulic motor which are adapted to operate in connection with said clutch unit.
Commercially available mechanical transmissions further require an additional reduction unit downstream of the reduction already provided by said transmission.
The above-described structure of mechanical transmissions is per se rather complicated and requires a considerable number of components which are not simple to manufacture and assemble.
Rather complicated hydraulic circuits are also required in order to coordinate the functions of the various units placed in separate casings.
The aim of the present invention is to provide a mechanical-hydrostatic transmission, particularly for tools and vehicles suitable for gardening, such as lawn-mowers or the like, which solves the above-noted drawbacks of conventional transmissions, particularly achieving considerable structural simplification, improving both the manufacture of the transmission and its sturdiness and operating functionality during use.
Within the scope of this aim, an object of the present invention is to provide a mechanical-hydrostatic transmission which allows a numerically large component reduction, with a consequent production cost reduction without however impairing operating functionality.
Another object of the present invention is to provide a mechanical-hydrostatic transmission which has a wide adjustment range and reduction variability and therefore does not require additional auxiliary reduction units arranged downstream of it.
Another object of the present invention is to provide a mechanical-hydrostatic transmission which requires a hydraulic circuit system which is simple and at the same time highly functional and safe, owing to the smaller number of components at risk of failure.
Another object of the present invention is to provide a mechanical-hydrostatic transmission which is functionally flexible with respect to the most disparate requirements of the application and of the vehicle on which it can be installed.
These and other objects which will become better apparent hereinafter are achieved by a mechanical-hydrostatic transmission, particularly for tools and vehicles suitable for gardening, such as lawn-mowers or the like, characterized in that it comprises a reduction unit, a clutch unit, an oil pump and a hydraulic motor which are integrated and contained within a single casing, said pump and said clutch unit being arranged coaxially on a first shaft which is connected externally, by means of a coupling, to motor means, said pump being hydraulically connected to said hydraulic motor and said hydraulic motor being in turn axially associated with a second shaft from which a power take-off extends, said casing containing kinematic connections for transmitting motion to the driving wheels.